A randomised trial of the effect of the glycine reuptake inhibitor Org 25935 on cognitive performance in healthy male volunteers.

OBJECTIVE: Cognitive impairment is integral to many neurological illnesses. Specific enhancement of glutamatergic transmission may improve memory and learning. Org 25935 increases the synaptic availability of glycine, an obligate co-agonist with glutamate at N-methyl-D-aspartate receptors. We hypothesised that Org 25935 would acutely improve the learning and memory of healthy volunteers. METHODS: A randomised, double-blind, parallel-group, single-dose study of Org 25935 and placebo was carried out. Thirty-two healthy male volunteers took either 12-mg Org 25935 or matching placebo and were later assessed with the manikin task, digit span and verbal memory tests. Systematic assessments of cardiovascular and adverse events were also taken. RESULTS: There was no effect of Org 25935 on reaction time, number of correct responses or learning (greater or slower improvement over successive tasks) compared with placebo. Org 25935 caused significantly more dizziness and drowsiness compared with placebo; these side effects were mainly mild. CONCLUSIONS: A single dose of Org 25935 does not improve learning or memory in healthy male individuals. However, the drug was well tolerated, and it remains to be seen whether it would have a positive effect on cognition in patient groups with pre-existing cognitive deficits.

Changes in cardiovascular function after venlafaxine but not pregabalin in healthy volunteers: a double-blind, placebo-controlled study of orthostatic challenge, blood pressure and heart rate.

It is generally thought that venlafaxine raises blood pressure at higher doses; however, some studies have found no effect or a decrease in blood pressure. The aim of this study was to evaluate the cardiovascular (CV) effects of 3 weeks of dosing with venlafaxine, pregabalin and placebo on young healthy adults. Fifty-four participants, of mean age 23.1 years (sd 4.68), 29 male, were randomised into three parallel groups. Each group received one of the three drugs, dosed incrementally over a 3-week period to reach daily doses of 150 mg/day venlafaxine and 200 mg/day pregabalin. Blood pressure sphygmomanometer measurements, heart rate measurements, and orthostatic challenges recorded continuously beat-to-beat were performed weekly over this period and 5 days after treatment cessation. Results showed resting systolic blood pressure (SBP) and resting and standing diastolic blood pressure (DBP) and heart rate (HR) were significantly raised by venlafaxine compared with the pregabalin and placebo groups. SBP drop on standing was larger, the resulting overshoot was smaller, and recovery was slower on venlafaxine. HR recovery was significantly impaired by venlafaxine. CV changes were observed after only 1 week of dosing at 112.5 mg/day. These effects of venlafaxine are likely to be due to its action of noradrenergic reuptake inhibition.

Evaluation of the effects of venlafaxine and pregabalin on the carbon dioxide inhalation models of Generalised Anxiety Disorder and panic.

Previous studies have shown that subjective and objective symptoms of anxiety induced by 7.5% CO(2) inhalation can be attenuated by anxiolytics such as lorazepam and, to a lesser extent, paroxetine. Venlafaxine and pregabalin, two other licensed treatments for Generalised Anxiety Disorder, were used to further investigate the 7.5% and 35% CO(2) models of anxiety in healthy volunteers. Fifty-four participants were randomised to receive either placebo, venlafaxine or pregabalin. Study treatments were dosed incrementally over a three week period, to reach daily doses of 150 mg venlafaxine and 200mg pregabalin by the CO(2) challenge test day. Participants inhaled air 7.5% CO(2) for 20 minutes (single-blind presentation), and a non-blinded single vital capacity of 35% CO(2). Subjective ratings were recorded before and after each inhalation. Both 7.5% and 35% CO(2) inhalations produced the expected effects of increased ratings of symptoms of panic and anxiety, with increased blood pressure and heart rate. No significant treatment effects were found, although there were trends towards a reduction in feeling tense and nervous by both drugs compared with placebo during the 7.5% CO(2) challenge, and a reduction in alertness generally in the venlafaxine group compared with the pregabalin group. In contrast with the clear anxiolytic effects of benzodiazepines reported in several previous CO(2) studies, these findings suggest that the anxiogenic effects of CO(2) challenges are not significantly influenced by these serotonergic and GABAergic anxiolytics. This may be due to a lack of sensitivity of the CO(2) challenges in healthy volunteers to these drug types.

The effect of a clinically effective and non-effective dose of lorazepam on 7.5% CO2-induced anxiety.

Symptoms of anxiety induced by 7.5% CO2 inhalation can be attenuated by acute administration of GABA(A) receptor anxiolytics such as lorazepam and alprazolam. This study investigated if these effects are dose-related, by comparing a 0.5 mg dose (considered non-clinically effective) and a 2 mg dose of lorazepam (clinically effective) on 7.5% CO2 inhalation. Eighteen healthy males (mean age 20.6 years, SD 1.29), judged physically and mentally fit, attended three visits, each one week apart, to take each treatment in a randomised double-blind crossover design. Drugs were given 60 min prior to 20 min air inhalation, followed by 20 min 7.5% CO2 inhalation. The order of gas presentation was single blind. Subjective ratings using visual analogue scales (VAS) and questionnaires were recorded before and after each inhalation. Blood pressure (BP), heart rate (HR), respiration rate (RR) and expired CO2 were recorded during each inhalation. Inhalation of 7.5% CO2 significantly raised BP, HR, RR and expired CO2. Ratings of feeling like leaving the room were significantly lower on 2 mg compared with 0.5 mg and placebo, and dose-dependent trends were seen in scores for VAS fearful, anxious, stressed, tense, and worried. Results may be indicative of dose-dependent effects of lorazepam in a CO2 model of anxiety.

Effectiveness of barcoding for reducing patient specimen and laboratory testing identification errors: a Laboratory Medicine Best Practices systematic review and meta-analysis.

OBJECTIVES: This is the first systematic review of the effectiveness of barcoding practices for reducing patient specimen and laboratory testing identification errors. DESIGN AND METHODS: The CDC-funded Laboratory Medicine Best Practices Initiative systematic review methods for quality improvement practices were used. RESULTS: A total of 17 observational studies reporting on barcoding systems are included in the body of evidence; 10 for patient specimens and 7 for point-of-care testing. All 17 studies favored barcoding, with meta-analysis mean odds ratios for barcoding systems of 4.39 (95% CI: 3.05-6.32) and for point-of-care testing of 5.93 (95% CI: 5.28-6.67). CONCLUSIONS: Barcoding is effective for reducing patient specimen and laboratory testing identification errors in diverse hospital settings and is recommended as an evidence-based "best practice." The overall strength of evidence rating is high and the effect size rating is substantial. Unpublished studies made an important contribution comprising almost half of the body of evidence.

Effectiveness of automated notification and customer service call centers for timely and accurate reporting of critical values: a laboratory medicine best practices systematic review and meta-analysis.

OBJECTIVE: To conduct a systematic review of the evidence available in support of automated notification methods and call centers and to acknowledge other considerations in making evidence-based recommendations for best practices in improving the timeliness and accuracy of critical value reporting. DESIGN AND METHODS: This review followed the Laboratory Medicine Best Practices (LMBP) review methods (Christenson, et al. 2011). A broad literature search and call for unpublished submissions returned 196 bibliographic records which were screened for eligibility. 41 studies were retrieved. Of these, 4 contained credible evidence for the timeliness and accuracy of automatic notification systems and 5 provided credible evidence for call centers for communicating critical value information in in-patient care settings. RESULTS: Studies reporting improvement from implementing automated notification findings report mean differences and were standardized using the standard difference in means (d=0.42; 95% CI=0.2-0.62) while studies reporting improvement from implementing call centers generally reported criterion referenced findings and were standardized using odds ratios (OR=22.1; 95% CI=17.1-28.6). CONCLUSIONS: The evidence, although suggestive, is not sufficient to make an LMBP recommendation for or against using automated notification systems as a best practice to improve the timeliness of critical value reporting in an in-patient care setting. Call centers, however, are effective in improving the timeliness of critical value reporting in an in-patient care setting, and meet LMBP criteria to be recommended as an "evidence-based best practice."

Effectiveness of practices to reduce blood culture contamination: a Laboratory Medicine Best Practices systematic review and meta-analysis.

OBJECTIVES: This article is a systematic review of the effectiveness of three practices for reducing blood culture contamination rates: venipuncture, phlebotomy teams, and prepackaged preparation/collection (prep) kits. DESIGN AND METHODS: The CDC-funded Laboratory Medicine Best Practices Initiative systematic review methods for quality improvement practices were used. RESULTS: Studies included as evidence were: 9 venipuncture (vs. versus intravenous catheter), 5 phlebotomy team; and 7 prep kit. All studies for venipuncture and phlebotomy teams favored these practices, with meta-analysis mean odds ratios for venipuncture of 2.69 and phlebotomy teams of 2.58. For prep kits 6 studies' effect sizes were not statistically significantly different from no effect (meta-analysis mean odds ratio 1.12). CONCLUSIONS: Venipuncture and the use of phlebotomy teams are effective practices for reducing blood culture contamination rates in diverse hospital settings and are recommended as evidence-based "best practices" with high overall strength of evidence and substantial effect size ratings. No recommendation is made for or against prep kits based on uncertain improvement.

Rapid tryptophan depletion following cognitive behavioural therapy for panic disorder.

OBJECTIVE: The aim of this study was to examine the effect of rapid tryptophan depletion (RTD) combined with a panicogenic challenge in patients with panic disorder who had responded to treatment with cognitive behavioural therapy (CBT). We hypothesised that RTD (compared with the control drink) would result in an increase in anxiety symptoms when provoked by a panicogenic challenge with the benzodiazepine antagonist, flumazenil. METHODS: Nine patients with panic disorder who had responded to CBT received a tryptophan-free amino acid drink on one occasion and a control drink on the other in a double-blind crossover design. In addition, they received flumazenil and placebo infusions on each day. RESULTS: Our hypothesis regarding the effects of RTD was supported by findings of a significant interaction between RTD and flumazenil on measures from visual analogues scales (total) and the Spielberger State Anxiety inventory. A somewhat unexpected finding was that in this group of CBT responders, the panicogenic effect of flumazenil was not completely blocked by treatment. This meant that although four of the nine subjects (44%) reported a panicogenic effect of flumazenil on the RTD day, this was not significantly different from the rate of panic attacks in response to flumazenil on the control day. CONCLUSION: We suggest that the partial return of symptoms in response to flumazenil reflects a vulnerability to RTD in this group of panic disorder patients who had responded to treatment with CBT.

Effects of 7.5% CO2 challenge in generalized anxiety disorder.

We have previously developed a putative model of generalized anxiety disorder in healthy volunteers using a 20-minute 7.5% carbon dioxide (CO(2)) inhalation challenge. The aim of this study was to validate the 7.5% CO(2) paradigm by assessing its effects in patients with generalized anxiety disorder in a test-retest design. Twelve medication-free generalized anxiety disorder patients attended our lab for two study days. On each study day placebo (compressed air) and 7.5% CO(2) mixture were randomly administered over 20 min, at least 30 min apart, in a single blind, randomized, placebo-controlled cross-over design. Subjective ratings, cardiovascular measures and cortisol levels were collected throughout. CO(2) challenge significantly increased ratings for anxiety and other subjective symptoms associated with generalized anxiety disorder, compared with air. It also significantly increased systolic blood pressure on day 2, indicating increased autonomic arousal. There was no change between the two test days in mean anxiety rating scores, and there also appeared to be a correlation for individual scores on a number of the subjective measures. In conclusion, 20 min of 7.5% CO(2) gas inhalation increases anxiety responses in patients with generalized anxiety disorder, and this is reliable over time.

The administration of psilocybin to healthy, hallucinogen-experienced volunteers in a mock-functional magnetic resonance imaging environment: a preliminary investigation of tolerability.

This study sought to assess the tolerability of intravenously administered psilocybin in healthy, hallucinogen-experienced volunteers in a mock-magnetic resonance imaging environment as a preliminary stage to a controlled investigation using functional magnetic resonance imaging to explore the effects of psilocybin on cerebral blood flow and activity. The present pilot study demonstrated that up to 2 mg of psilocybin delivered as a slow intravenous injection produces short-lived but typical drug effects that are psychologically and physiologically well tolerated. With appropriate care, this study supports the viability of functional magnetic resonance imaging work with psilocybin.

Assessment of GABAA benzodiazepine receptor (GBzR) sensitivity in patients with alcohol dependence.

AIM: The aim of this study was to measure GABAA benzodiazepine receptor (GBzR) sensitivity in alcohol-dependent patients and compare with matched non-dependent drinkers. METHODS: Nine abstinent alcohol-dependent male patients, age matched with nine male non-dependent social drinkers, received an intravenous infusion of midazolam. Objective (saccadic eye movement slowing) and subjective (visual analogue scales) measurements were recorded at 15-min intervals for 2 h. RESULTS: There were no differences in objective or subjective measures. CONCLUSIONS: Our hypothesis that patients with alcohol dependence would have less slowing of their eye movements in response to this challenge, reflecting reduced GBzR sensitivity, was not confirmed. The reasons for this could mean that GBzR function returns to normal with abstinence, or that this paradigm is unable to measure the subtle subtype-specific changes in GBzR sensitivity that occur following dependent alcohol use.

Sexual health promotion: the barriers school nurses face.

This paper reports on the findings of a study which aimed to determine the contribution of school nurses to promoting sexual health within schools and whether occupational and professional boundaries impinged on the school nurses' ability to undertake this aspect of their role. The research was carried out across three Primary Care Trusts (PCTs). Data were collected using semi-structured interviews, a total of 30 school nurses (n=30) from across the three PCTs were included in the study. Analysis of the data indicated that barriers in the form of gate-keepers were present and they could impede the school nurse in fulfilling her role as a health educator. This gate-keeping existed across three 'tiers': the school governors, the school (as a collective organisation) and teachers. Nurses employed a variety of strategies to negotiate their way through these gatekeepers in order to access the classroom setting, key among them was their willingness to collaborate and co-operate, by 'slotting in' with the school, the curriculum and its timetable and 'fitting in' with the teachers, as their needs dictated.

The use of sleep measures to compare a new 5HT1A agonist with buspirone in humans.

The partial agonist buspirone has a REM (rapid eye movement) suppressing effect on human sleep probably via a 5HT(1A) receptor in the pontine area. Eptapirone is a new 5HT(1A) agonist with a greater intrinsic effect than buspirone. The objective of this study was to examine the effects of eptapirone on sleep architecture, particularly REM sleep, in normal volunteers and compare it with buspirone and placebo. This was a randomized, double-blind placebo-controlled four-way crossover study in 12 healthy volunteers. Volunteers were screened to ensure that they had normal overnight sleep EEG (electroencephalogram) and were extensive CYP 2D6 metabolizers. Sleep was recorded on pairs of nights on four occasions, with medication being taken before the second night. Treatments were eptapirone 1.5mg at 10 AM, eptapirone 1.5mg at 11 PM, buspirone 20mg at 11 PM and placebo. Standard measures of sleep were derived and compared among the four treatments using ANOVA. REM sleep was significantly suppressed supporting the proposition that activation of post-synaptic 5HT(1A) receptors reduces REM sleep. Sleep fragmentation increased by both drugs. REM sleep suppression was significantly greater with morning eptapirone than with buspirone. Wakefulness in sleep was significantly greatest after morning eptapirone. REM sleep effects were greatest after evening eptapirone, suggesting a greater effect on central serotonin receptors than that of buspirone.

Tryptophan depletion reverses the therapeutic effect of selective serotonin reuptake inhibitors in social anxiety disorder.

BACKGROUND: Tryptophan depletion studies have suggested that central serotonin (5-hydroxytryptamine, 5-HT) function mediates the therapeutic effect of selective serotonin reuptake inhibitors (SSRIs) in depression and panic disorder. The present study tested the hypothesis that temporary reduction in central 5-HT transmission, through acute tryptophan depletion, could reverse the therapeutic effect of the SSRIs in social anxiety disorder (SAD) patients. METHODS: Fourteen patients with SAD who showed sustained clinical improvement with SSRI treatment underwent tryptophan depletion in a double-blind, placebo-controlled, crossover design, over 2 days 1 week apart. At the peak time of depletion, the participants also underwent three behavioral challenges: autobiographical script, verbal task, and neutral script. Psychological outcome was assessed with the Spielberger State Anxiety Inventory (STAI) Form Y-1 and visual analog scales (VAS) measuring anxiety, depression, and somatic symptoms. RESULTS: Anxiety was significantly increased on the depletion day compared with the control day, both on the STAI Form Y-1 and composite VAS score. Furthermore, there was a significant depletion x time interaction, explained mainly by the anxiogenic effect of the autobiographical script. In contrast, the verbal and the neutral tasks failed to differentiate between depletion and placebo. CONCLUSIONS: Tryptophan depletion induced significant increase of anxiety in treated SAD patients, which was more prominent during the recital of an autobiographical script. This finding supports the notion that SSRIs improve social anxiety by increasing 5-HT availability. The autobiographical script seems to be a more robust challenge test for SAD than the stressful verbal task.

Correlation of subjective and objective sleep measurements at different stages of the treatment of depression.

Studies of the correlation of subjective and objective sleep measures in depressed patients have produced mixed results so far. Further, they were carried out in sleep laboratories and tended to obtain one-off assessments, thus not taking into account the effect of treatment. We investigated forty (40) patients over the course of 8-week treatment of depression with either paroxetine or nefazodone. We used home polysomnography at baseline, nights 3 and 10, and week 8 of treatment, with extensive assessments of subjective sleep, the morning after each sleep recording. The patients were able to judge accurately their total sleep time and sleep onset latency, both before and during treatment. However, they were inaccurate in estimating the number of times they woke up during the night. Sleep satisfaction correlated negatively with Stage 1 sleep at baseline. Sleep quality was represented by a combination of subjective parameters measuring the ease of initiation and maintenance of sleep, and it appeared to derive from slow wave sleep and sleep continuity as seen in polysomnography. The partial discrepancy between subjective and objective measures suggests that a cognitive element is combined with the biological element to produce the sleep problems reported by depressed patients.

Effects on sleep architecture of pindolol, paroxetine and their combination in healthy volunteers.

RATIONALE: The combination of pindolol with a serotonergic antidepressant has been used to speed up the antidepressant response and to augment in cases of resistant depression. Animal studies have suggested that this increased response occurs because of 5HT(1A) antagonist properties of pindolol, which in combination with a serotonergic antidepressant produces a synergistic increase in 5HT in the synapse. OBJECTIVES: To test whether the combination of pindolol with a serotonergic antidepressant produces a synergistic increase in synaptic 5HT by examining the effects on measures of sleep, psychomotor performance and ratings of anxiety. METHODS: Twelve healthy male volunteers took part in randomised crossover study in which they received paroxetine 20 mg/day (or its placebo) for 9 days with a washout period of 5 days between. On day 7 and 9 of each treatment they also received pindolol 2.5 mg (or its placebo) three times a day. Sleep EEG recordings were made on each of the nights on pindolol (or its placebo) and ratings of saccadic eye movement parameters, subjective sleep, anxiety and other adverse events recorded on the following days. Four drug conditions were therefore tested: placebo, pindolol alone, paroxetine alone and paroxetine+pindolol. RESULTS. The combination of paroxetine+pindolol produced an increase in REM suppression and a reduction in SWS compared with other drug combinations. There were no significant effects on the other measures of 5HT function recorded in this study. CONCLUSIONS: REM suppression by the combination was approximately equal to the sum of REM suppression by each drug individually and thus does not show a synergistic effect. However, there was a significant reduction in SWS produced by only the combination treatment, which may suggest a specific effect of the combination on non-REM sleep mechanisms.

Parental occupation and neural tube defect-affected pregnancies among Mexican Americans.

In a case-control study, we examined whether parental occupational exposures were related to neural tube defect (NTD)-affected pregnancies among Mexican Americans living along the Texas-Mexico border. Case women were 184 Mexican-American women with NTD-affected pregnancies; control women were 225 study-area residents who delivered normal babies during the same period as the case women. The women were interviewed in person about maternal and paternal occupations and work exposures during the periconceptional period. Compared with control women, case women were more likely to have had occupational exposures to solvents (odds ratio [OR], infinity; 95% confidence interval [CI], 2.4-infinity) and also were more likely to have worked in cleaning (OR 9.5; 95% CI, 1.1 to 82.2) or health care occupations (OR 3.0; 95% CI, 1.0 to 9.0) than control women. No compelling associations were found between paternal work exposures or occupations and NTDs in offspring in this population.

Inhalation of 35% CO(2) results in activation of the HPA axis in healthy volunteers.

BACKGROUND: The hypothalamo-pituitary-adrenal (HPA) axis is a major stress responsive system in humans. Although there are numerous ways of testing responsiveness of the HPA in experimental animals, this is much more difficult in man. Hypercapnea is a very stressful stimulus for humans and has been used as an anxiogenic probe in psychiatric patients. We have now investigated whether the simple challenge of a single 35% inhalation of CO(2) activates the neuroendocrine system as evidenced by changes in HPA activity, as well as cardiovascular and subjective responses, in healthy volunteers. METHODS: Fourteen healthy male volunteers were recruited. They underwent single vital capacity inhalation of room air and 35% CO(2), in a single blind fashion. Neuroendocrine, cardiovascular and subjective fear measures were taken at regular intervals. RESULTS: CO(2) inhalation produced significant activation of the HPA axis in all subjects, as measured with plasma cortisol. Heart rate was decreased and systolic blood pressure was significantly increased shortly after the inhalation of CO(2). The subjects reported short-lived symptoms of fear with the experimental gas. CONCLUSIONS: Single vital capacity inhalation of 35% CO(2) activated the HPA axis in healthy volunteers. It also had a significant cardiovascular and psychological (anxiogenic) effect, as expected from previous published studies. The test is potentially useful in studying the responsivity of the HPA axis in health and disease.

Does 5-HT restrain panic? A tryptophan depletion study in panic disorder patients recovered on paroxetine.

The neurobiological basis of panic disorder has not been clearly established, although a role for serotonin (5-HT) has been postulated. It is clear that drugs which increase 5-HT neurotransmission are effective in treating the condition but how they do so remains a point of debate. The aim of this study was to determine if lowering brain serotonin activity using the technique of tryptophan depletion provoked a short-term relapse of panic symptoms in patients with panic disorder who had responded to drug treatment. Fourteen patients with panic disorder who had responded to treatment with the selective serotonin reuptake inhibitor (SSRI) paroxetine received a tryptophan-free amino acid drink on one occasion and a control drink on the other in a double-blind crossover design. In addition, they received an infusion of flumazenil (used as a pharmacological challenge) and placebo on each day. The tryptophan depleted drink produced an 87% reduction in plasma tryptophan concentration. Flumazenil produced a panic attack (defined by changes in the panic inventory) in seven out of 14 patients when tryptophan depleted and one out of 14 on the control day (p < 0.02). Three patients also experienced temporary depressive symptoms when tryptophan depleted, with no mood changes being seen on the control days. We conclude that rapid lowering of brain serotonin function can allow the precipitation of panic symptoms in response to flumazenil in panic disorder patients who have responded to treatment with an SSRI. This implies that in panic disorder increased 5-HT availability is important in maintaining the response to SSRIs.

GABAAbenzodiazepine receptor (GBzR) sensitivity: test-retest reliability in normal volunteers.

Rationale: Alcohol, benzodiazepines and barbiturates act through the GABA(A) benzodiazepine receptor (GBzR). Patients with some forms of anxiety disorder have reduced GBzR sensivity, although it is not clear whether this is a state or a trait phenomenon. We have developed a paradigm for assessing GBzR sensitivity using slowing of saccadic eye movements in response to intravenous midazolam.Objectives: To obtain reliability data for GBzR sensitivity in normal volunteers and to look at factors that might influence sensitivity.Methods: Five male volunteers received an intravenous infusion of midazolam (50 &mgr;m/kg) given over 10 min. Saccadic eye movement velocity (SEMV) was recorded at baseline and at 15 min intervals up to 120 min post infusion. Blood was taken at these times for mixazolam assay. The study was repeated at 4 weeks. Pharmacodynamic (PD) effect was calculated by measuring area under the curve (AUC) of SEMV plot versus time for each individual on both study days. Pharmacokinetic (PK) effect was calculated by measuring AUC from t = 0 to t = 120 min. Ratio of PD/PK effect was then calculated to give a measure of GBzR sensitivity.Results: There was a very strong correlation between individual GBzR sensitivity on both study days (r = 0.99; p = 0.008).Conclusion: The results suggest that GBzR sensitivity is relatively stable over time in normal volunteers and that the paradigm described has good reliability. Copyright 2000 John Wiley & Sons, Ltd.